Mesh deforms incorrectly
How did you rig your dragon?
&quot;manually&quot; you would do weight painting for your bone that parts you want to be deformend if that bone moves.
I did that for your case and i got:

But your vertex group (i just checked for that special bone) didn't had any weights!?, that's why i asked how you did setup your rig.
and i did this weight painting for this vertex group: